java内存动态编译执行

1.package org.jui.core.dynamic; 

public class DynaCompTest {

    public static void main(String[] args) throws Exception {

        String fullName = "DynaClass";

        StringBuilder src = new StringBuilder();

        src.append("public class DynaClass {\n");

        src.append("    public String toString() {\n");

        src.append("        return \"Hello, I am \" + ");

        src.append("this.getClass().getSimpleName();\n");

        src.append("    }\n");

        src.append("}\n");

 

        System.out.println(src);

        DynamicEngine de = DynamicEngine.getInstance();

        Object instance =  de.javaCodeToObject(fullName,src.toString());

        System.out.println(instance);

2.package org.jui.core.dynamic;

 

import javax.tools.*;

import java.util.ArrayList;

import java.util.List;

import java.util.Arrays;

import java.net.URL;

import java.net.URLClassLoader;

import java.io.File;

 

public class DynamicEngine {

    private static DynamicEngine ourInstance = new DynamicEngine();

 

    public static DynamicEngine getInstance() {

        return ourInstance;

    }

    private URLClassLoader parentClassLoader;

    private String classpath;

    private DynamicEngine() {

        this.parentClassLoader = (URLClassLoader) this.getClass().getClassLoader();

        this.buildClassPath();

    }

    private void buildClassPath() {

        this.classpath = null;

        StringBuilder sb = new StringBuilder();

        for (URL url : this.parentClassLoader.getURLs()) {

            String p = url.getFile();

            sb.append(p).append(File.pathSeparator);

        }http://www.huiyi8.com/jiaoben/ JQuery特效

        this.classpath = sb.toString();

    }

    public Object javaCodeToObject(String fullClassName, String javaCode) throws IllegalAccessException, InstantiationException {

        long start = System.currentTimeMillis();

        Object instance = null;

        JavaCompiler compiler = ToolProvider.getSystemJavaCompiler();

        DiagnosticCollector<JavaFileObject> diagnostics = new DiagnosticCollector<JavaFileObject>();

        ClassFileManager fileManager = new ClassFileManager(compiler.getStandardFileManager(diagnostics, null, null));

 

        List<JavaFileObject> jfiles = new ArrayList<JavaFileObject>();

        jfiles.add(new CharSequenceJavaFileObject(fullClassName, javaCode));

        List<String> options = new ArrayList<String>();

        options.add("-encoding");

        options.add("UTF-8");

        options.add("-classpath");

        options.add(this.classpath);

 

        JavaCompiler.CompilationTask task = compiler.getTask(null, fileManager, diagnostics, options, null, jfiles);

        boolean success = task.call();

 

        if (success) {

            JavaClassObject jco = fileManager.getJavaClassObject();

            DynamicClassLoader dynamicClassLoader = new DynamicClassLoader(this.parentClassLoader);

            Class clazz = dynamicClassLoader.loadClass(fullClassName,jco);

            instance = clazz.newInstance();

        } else {

            String error = "";

            for (Diagnostic diagnostic : diagnostics.getDiagnostics()) {

                error = error + compilePrint(diagnostic);

        long end = System.currentTimeMillis();

        System.out.println("javaCodeToObject use:"+(end-start)+"ms");

        return instance;

    private String compilePrint(Diagnostic diagnostic) {

        System.out.println("Code:" + diagnostic.getCode());

        System.out.println("Kind:" + diagnostic.getKind());

        System.out.println("Position:" + diagnostic.getPosition());

        System.out.println("Start Position:" + diagnostic.getStartPosition());

        System.out.println("End Position:" + diagnostic.getEndPosition());

        System.out.println("Source:" + diagnostic.getSource());

        System.out.println("Message:" + diagnostic.getMessage(null));

        System.out.println("LineNumber:" + diagnostic.getLineNumber());

        System.out.println("ColumnNumber:" + diagnostic.getColumnNumber());

        StringBuffer res = new StringBuffer();

        res.append("Code:[" + diagnostic.getCode() + "]\n");

        res.append("Kind:[" + diagnostic.getKind() + "]\n");

        res.append("Position:[" + diagnostic.getPosition() + "]\n");

        res.append("Start Position:[" + diagnostic.getStartPosition() + "]\n");

        res.append("End Position:[" + diagnostic.getEndPosition() + "]\n");

        res.append("Source:[" + diagnostic.getSource() + "]\n");

        res.append("Message:[" + diagnostic.getMessage(null) + "]\n");

        res.append("LineNumber:[" + diagnostic.getLineNumber() + "]\n");

        res.append("ColumnNumber:[" + diagnostic.getColumnNumber() + "]\n");

        return res.toString();

3.package org.jui.core.dynamic;

import javax.tools.JavaFileObject;

import javax.tools.SimpleJavaFileObject;

import java.net.URI;

 

public class CharSequenceJavaFileObject extends SimpleJavaFileObject {

    private CharSequence content;

    public CharSequenceJavaFileObject(String className,

                                      CharSequence content) {

        super(URI.create("string:///" + className.replace('.', '/')

                + JavaFileObject.Kind.SOURCE.extension), JavaFileObject.Kind.SOURCE);

        this.content = content;

    @Override

    public CharSequence getCharContent(

            boolean ignoreEncodingErrors) {

        return content;

4.package org.jui.core.dynamic;

 

import javax.tools.*;

import java.io.IOException;

import java.security.SecureClassLoader;

 

public class ClassFileManager extends

        ForwardingJavaFileManager {

    public JavaClassObject getJavaClassObject() {

        return jclassObject;

    private JavaClassObject jclassObject;

    public ClassFileManager(StandardJavaFileManager

        standardManager) {

        super(standardManager);

    @Override

    public JavaFileObject getJavaFileForOutput(Location location,

        String className, JavaFileObject.Kind kind, FileObject sibling)

            throws IOException {

            jclassObject = new JavaClassObject(className, kind);

        return jclassObject;